JP7143200B2 - image forming device - Google Patents

Description

The present invention relates to an image forming apparatus that performs single-sided printing and double-sided printing.

The configuration of the image forming apparatus includes a configuration that prints on paper while conveying the paper in the vertical direction (hereinafter referred to as a vertical pass machine) and a configuration that prints on paper while conveying the paper in the horizontal direction (hereinafter referred to as a horizontal pass machine). ). For example, in single-sided printing of a vertical pass machine, the front side (first page) image is printed on the upper side (first side) of the paper set in the feed cassette, and the front side image is printed (set The paper is ejected with the top side of the paper facing down. On the other hand, in the double-sided printing of the vertical pass machine, the image of the back side (second page) is printed on the upper side of the paper set in the feed cassette. After that, the paper is reversed in the double-sided transport path, the image of the front side (first page) is printed on the bottom side (second side) of the paper, and the bottom side (of the set paper) on which the front side image is printed faces down. Paper is ejected toward That is, in the vertical pass machine, single-sided printing and double-sided printing differ in whether the front side image is printed on the upper side or the lower side of the paper set in the feed cassette. For this reason, when printing images on paper with different front and back sides, such as preprinted paper or pre-punched paper, the vertical pass machine faces up depending on whether single-sided or double-sided printing is performed. It changes whether to set it in the feeding cassette.

Here, during single-sided printing, according to the attribute of the paper feed unit, the paper is passed through the duplex transport path, the paper is reversed, and the image of the front side is printed on the bottom side of the paper. It has been known. Also, during 2-sided printing, depending on the type of paper, the front side image is not printed on the bottom side of the paper. There is a technique for printing an image on the back side of the paper (Patent Document 1). As a result, even in the vertical pass machine, it is not necessary to change the top and bottom setting directions of the paper between single-sided printing and double-sided printing.

JP-A-2003-50482

However, in the above-described technique of passing a sheet through the duplex transport path with single-sided printing according to the attribute of the paper feed unit, even a sheet having the same top surface and bottom surface is passed through the duplex transport path with single-sided printing, resulting in slower printing. Further, in Japanese Patent Application Laid-Open No. 2002-200000, printing is slowed down because the paper is reversed before double-sided printing.

Accordingly, the present invention provides an image forming apparatus that performs single-sided printing in a first mode or a second mode according to attribute information corresponding to the paper type.

An image forming apparatus according to an embodiment of the present invention comprises:
a paper feed unit having a plurality of cassettes on which paper is stacked;
a transport path along which the paper fed from the paper feed unit is transported;
an image forming unit that forms an image on the sheet conveyed on the conveying path;
a reversing unit for reversing the paper that has passed through the image forming unit;
a re-conveying path through which the sheet reversed by the reversing section is conveyed;
a discharge unit for discharging the paper on which the image is formed;
a storage unit that stores attribute information corresponding to paper types;
a control unit that receives a print job including the paper type and print settings for single-sided printing or double-sided printing;
When the print setting is the double-sided printing, the control unit causes the image forming unit to form an image on the first surface of the sheet transported from the first cassette of the plurality of cassettes to the transport path, and The sheet on which the image is formed is reversed by the reversing section, and an image is formed by the image forming section on the second side opposite to the first side of the sheet conveyed to the conveying path through the re-conveying path. , ejecting the paper to the ejection unit;
When the print setting is single-sided printing, the control unit determines which of the first mode and the second mode to execute based on the attribute information corresponding to the paper type included in the print job. to judge
When executing the first mode, the control unit causes the image forming unit to form an image on the first surface of the sheet conveyed from the first cassette to the conveying path, and the image is formed on the first surface of the sheet. discharging the paper to the discharge unit without passing through the re-conveyance path;
When executing the second mode, the control unit causes the image forming unit to not form an image on the first surface of the sheet transported from the first cassette to the transport path, and the sheet is transported to the transport path. The image forming section forms an image on the second side opposite to the first side of the sheet reversed by the reversing section and conveyed to the conveying path through the re-conveying path, and discharges the sheet to the discharging section. death,
The paper is discharged to the discharge unit with the upper surface of the paper stacked in the first cassette in a different orientation between the double-sided printing and the single-sided printing in which the first mode is set,
The paper is ejected to the ejection section in the same direction for the upper surface of the paper stacked in the first cassette for the double-sided printing and for the single-sided printing in which the second mode is set. do.

According to the present invention, single-sided printing can be performed in the first mode or the second mode according to the attribute information corresponding to the paper type.

The figure which shows MFP. 3 is a block diagram of the MFP control system; FIG. The figure which shows an operation part. FIG. 10 is a view showing a paper attribute setting screen; FIG. FIG. 10 is a diagram showing a paper transport path when the print side priority mode is OFF in single-sided printing; FIG. 4 is a diagram showing a paper transport path in double-sided printing; FIG. 4 is an explanatory diagram showing on which side an image on the front side is formed, on the top side or the bottom side of the paper; 4 is a flow diagram showing a printing operation performed by a CPU; FIG. 10 is a view showing a print driver screen when instructing printing from a PC; FIG. 4 is a diagram showing the data structure of a print job; FIG. 4 is a diagram showing the data structure of paper feed units and paper types; 4 is a flow chart showing a paper feed unit automatic selection operation executed by a CPU; FIG. 10 is a diagram showing a screen for setting automatic selection of a paper feed unit;

EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing this invention is demonstrated using drawing.

(Image forming device)
With reference to FIG. 1, a multi-function peripheral (hereinafter referred to as MFP) 100 will be described as an example of an image forming apparatus that forms an image on a recording medium (hereinafter referred to as paper). FIG. 1 is a diagram showing an MFP 100. As shown in FIG. The MFP 100 includes a scanner unit (reading unit) 301 that reads an image of a document, a printer unit (image forming unit) 302 that forms an image on paper, and a finisher (post-processing unit) that performs bookbinding processing on the paper on which an image has been formed. 104. A scanner unit 301 as an image input device illuminates a document placed on a platen glass (not shown), scans reflected light from the document with a CCD line sensor, and converts the image of the document into image data. . Color determination and size determination of the document are performed based on the converted image data. A printer unit 302 as an image output device prints an image on paper based on image data. In this embodiment, the printer unit 302 forms an image on paper using an electrophotographic method. However, the printer unit 302 may form an image on paper using various types of printing methods such as an inkjet method, an electrostatic method, and a thermal transfer method, without being limited to the electrophotographic method. A feed cassette 601 is provided below the printer unit 302 . Sheets are stacked in the feed cassette 601 . The paper is, for example, plain paper, recycled paper, thick paper, second original drawing paper, OHP paper, colored paper, pre-punched paper, pre-printed paper, letterhead or label paper. A finisher 104 performs bookbinding processing such as stapling and folding on sheets on which images have been formed. Starting and stopping of the print operation are controlled by the CPU 201 (FIG. 2) of the controller 101 provided in the main body of the MFP 100 .

(control system)
FIG. 2 is a block diagram of the control system 10 of the MFP 100. As shown in FIG. The control system 10 has a controller 101 that controls the entire MFP 100 . The controller 101 is electrically connected to a scanner engine 102 that controls the scanner unit 301 and a printer engine 103 that controls the printer unit 302 . Controller 101 is electrically connected to finisher 104 , network interface 105 , operation unit 106 and modem 108 . The scanner engine 102 and printer engine 103 are controlled by the controller 101 . The printer engine 103 is electrically connected to the finisher 104 . The finisher 104 can collectively staple a plurality of sheets output from the printer unit 302 . A finisher 104 is controlled by the controller 101 or the printer engine 103 .

A network interface 105 provides bidirectional communication between an external device and the controller 101 . The network interface 105 is connected to a personal computer (hereinafter referred to as PC) 107 as an external device via a local area network (hereinafter referred to as LAN) 220 . Controller 101 is capable of two-way communication connection with PC 107 via network interface 105 . Modem 108 connects to public line network 109 . The controller 101 inputs and outputs facsimile images via the modem 108 . The operation unit 106 is composed of a liquid crystal display unit 401 and a keyboard 204 . The operation unit 106 displays information from the controller 101 and transmits instructions from the user to the controller 101 . Functions that can be executed from the operation unit 106 can also be executed from the PC 107 connected to the network interface 105 .

The controller 101 has a CPU (control unit) 201, a memory (storage unit) 202, a ROM 210, and a DISK (storage unit) 211 such as a hard disk. The CPU 201 is connected to the memory 202 , operation unit 106 , ROM 210 and DISK 211 via a bus 209 . Various programs and data are stored in the DISK 211 or ROM 210 . The CPU 201 reads programs and data from the DISK 211 or ROM 210 to the memory 202 as necessary, and executes the programs. The DISK 211 may be detachable from the MFP 100 or may be built in the MFP 100 . The program may be downloaded from another MFP via LAN 220 or public line network 109 and stored in DISK 211 .

The memory 202 may be a volatile memory, a non-volatile memory, or may have both volatile and non-volatile memory functions. Alternatively, the memory 202 may have a volatile memory function and the DISK 211 may have a nonvolatile memory function. Memory 202 and/or DISK 211 may be memory media removable from MFP 100 . The CPU 201 displays information by writing data to the liquid crystal display unit 401 of the operation unit 106 . The CPU 201 inputs instructions from the user by reading data from the keyboard 204 or the liquid crystal display unit 401 which is a touch panel. Information input to the CPU 201 is stored in the memory 202, DISK 211, or CPU 201 and used for various processes.

Bus 209 is connected to network interface 105 . The CPU 201 performs two-way communication with an external device such as the PC 107 by reading or writing data from the network interface 105 . Bus 209 is connected to modem 108 . The CPU 201 uses the modem 108 to transmit or receive facsimile images through the public line network 109 . A bus 209 is connected to the printer engine 103 , finisher 104 and scanner engine 102 . The CPU 201 reads and writes data to the printer engine 103, the finisher 104, and the scanner engine 102, performs printing (image formation), bookbinding, and scanning (image reading) operations, and acquires various statuses. Image data is input from the scanner engine 102 or network interface 105 to the controller 101 and stored in the DISK 211 or memory 202 . Alternatively, image data can be stored in a removable memory medium in advance, and the memory medium can be loaded into MFP 100 to load the image data from the memory medium into controller 101 .

Note that the image forming apparatus of this embodiment is not limited to the MFP 100 and may be an SFP (Single Function Printer). Alternatively, the scanner unit 301 , the printer unit 302 and the finisher 104 may be provided as individual peripheral devices on the LAN 220 or the public line network 109 instead of inside the MFP 100 and controlled by the controller 101 .

(operation unit)
The operation unit 106 will be described with reference to FIG. FIG. 3 is a diagram showing the operation unit 106. As shown in FIG. The liquid crystal display unit 401 has a touch panel sheet pasted on the liquid crystal. A liquid crystal display unit 401 displays an operation screen and soft keys. When the displayed soft key is touched by the user, the liquid crystal display unit 401 transmits the position information to the CPU 201 of the controller 101 . The keyboard 204 has a start key 402 , a stop key 404 , ten keys 405 and a user mode key 406 . For example, when reading an image of a document, when the user presses the start key 402, the operation of reading the image of the document is started. A two-color LED 403 of green and red is provided in the center of the start key 402 . When the bicolor LED 403 is green, the start key 402 is ready for use. When the two-color LED 403 emits red light, the start key 402 is disabled. When the stop key 404 is pressed, the running operation is stopped. A numeric keypad 405 is composed of a group of numeric and letter buttons. The user uses the numeric keypad 405 to set the number of copies and to instruct screen switching on the liquid crystal display unit 401 . A user mode key 406 is pressed by the user when performing device settings.

((Paper attribute setting screen))
An example of a paper attribute setting screen 501 displayed on the liquid crystal display unit 401 according to an instruction from the CPU 201 of the controller 101 will be described with reference to FIG. FIG. 4A shows a paper attribute setting screen 501. FIG. A paper attribute setting screen 501 displays setting values of paper attributes (attribute information) 502 of paper identifiers (hereinafter referred to as paper IDs) as paper types. Paper attributes 502 include basis weight, surface properties, characteristics, color, and preprinted paper (hereinafter referred to as print surface priority mode) 503 . The user can change the set values of the paper attributes 502 on the paper attribute setting screen 501 . The paper attributes 502 are saved in the memory (storage unit) 202 . A print side priority mode 503 is a print side priority attribute for determining whether or not to pass the paper through the re-conveyance path 612 (FIG. 6) for double-sided printing in the case of single-sided printing. The print surface priority mode 503 can be set to ON/OFF in FIG. 4B. When the print side priority mode 503 is ON 505, in the case of single-sided printing, the paper is passed through the re-conveyance path 612 (FIG. 6) for double-sided printing without printing on the first side (upper surface) of the paper, and the paper is reversed. After that, the front side image is printed on the second side (bottom side) opposite to the first side of the paper. As a result, for both single-sided printing and double-sided printing, the front side image is printed on the bottom side of the paper set in the feed cassette 601, and the paper is discharged to the discharge section 605 with the bottom side on which the front side image is printed facing downward. be. When the print surface priority mode 503 is OFF 504, printing is performed on the first surface (upper surface) of the paper in the case of single-sided printing.

(Paper transport path)
With reference to FIG. 5, the conveying path of the sheet S when the print side priority mode 503 is OFF in single-sided printing of the MFP 100 of this embodiment will be described. FIG. 5 is a diagram showing the transport path of the sheet S when the print surface priority mode 503 is OFF in single-sided printing. When the print side priority mode 503 is OFF in single-sided printing, the MFP 100 operates in the speed priority mode (first mode). The MFP 100 is configured to print on the sheet S while conveying the sheet S in the vertical direction (hereinafter referred to as a vertical pass machine). The conveying path 611 extends from the feed roller 621 to the discharge roller 622 through the transfer section 602 and the fixing section 604 . In FIG. 5, for the sake of explanation, the upper surface of the sheets S stacked in the feed cassette 601 is given a .DELTA. mark.

A sheet feeding cassette 601 as a sheet feeding unit comprises a plurality of sheet feeding stages (hereinafter referred to as a sheet feeding unit). In this embodiment, the plurality of paper feeders includes a first paper feeder 631 , a second paper feeder 632 , a third paper feeder 633 and a fourth paper feeder 634 . The plurality of paper feed units may further have a fifth paper feed unit 635 as a manual feed tray. The sheet S is conveyed from the feed cassette 601 to the position P1 by the feed roller 621 . The toner image is transferred to the sheet S by the transfer unit 602 at the position P1. The sheet S is transported to position P2. At position P<b>2 , the toner image is fixed onto the sheet S by the fixing unit 604 . The sheet S having the front side image formed on the top side is discharged to the discharge section 605 by the discharge rollers 622 with the top side on which the front side image is formed facing downward. In this way, when the print side priority mode 503 is OFF in single-sided printing, the front side image is formed on the upper side of the sheet S set in the feed cassette 601, and the upper side on which the front side image is formed faces downward. Then, the sheet S is discharged to the discharge unit 605 . Here, an image formed in single-sided printing is referred to as an image on the front side.

A conveying path of the sheet S in double-sided printing of the MFP 100 of this embodiment will be described with reference to FIG. The re-conveying path 612 extends from between the fixing section 604 and the discharge roller 622 to between the feeding roller 621 and the transfer section 602 . A reversing section 624 is provided in the re-conveying path 612 . The reversing section 624 is provided with a reversing path 613 and reversing rollers 623 . The reversing section 624 reverses the sheet S that has been conveyed on the conveying path 611 and passed through the printer section 302 and conveys it to the re-conveying path 612 . As in FIG. 5, in FIG. 6, the upper surface of the sheets S stacked in the feed cassette 601 is given a .DELTA. mark for the sake of explanation. The transport of the paper S fed from the feed cassette 601 for forming the image of the back side on the upper surface (first surface) of the paper S is the same as in FIG. 5, and is therefore not shown in FIG. After the back side image is fixed on the upper surface (first surface) of the sheet S, the sheet S is conveyed to the position P3 of the reversing path 613 by the action of a conveying path switching flapper (not shown). The sheet S is switched back by the reverse rotation of the reversing roller 623, and is conveyed from the position P3 to the position P4 on the re-conveying path 612 with the trailing edge of the sheet S as the leading edge. The paper S returns to the transport path 611 again, and the toner image on the surface is transferred to the lower surface (second surface) of the paper S by the transfer unit 602 at position P1. The toner image on the surface of the sheet S is fixed to the lower surface (second surface) of the sheet S by the fixing unit 604 at the position P2. The sheet S having the front image formed on the bottom surface (second surface) is discharged to the discharge unit 605 by the discharge rollers 622 with the bottom surface (second surface) having the front image formed thereon facing downward. In this way, in double-sided printing, the front side image is formed on the bottom side (second side) of the sheet S set in the feed cassette 601, and the bottom side (second side) on which the front side image is formed faces downward. Then, the sheet S is discharged to the discharge unit 605 . Here, of the two images to be formed on both sides of the sheet S in double-sided printing, the image on the first page is called the image on the front side, and the image on the second page is called the image on the back side. In double-sided printing, the image on the back side, which is the image on the later page, is formed on the sheet S before the image on the front side, which is the image on the previous page.

In this embodiment, when an image is printed on paper S having different front and back surfaces, such as pre-punched paper, pre-printed paper, letterhead, or label paper, the paper S is placed in the feed cassette 601 with the front side of the paper S facing downward. loaded. In the case of the fifth paper feeding unit 635 as a manual feed tray, the paper S is stacked on the fifth paper feeding unit 635 with the surface of the paper S facing upward. The user sets the print surface priority mode of the paper ID of the paper S to ON. In the case of double-sided printing, as described above, the image of the back surface is formed on the upper surface (back surface) of the paper S set in the feed cassette 601, the image of the front surface is formed on the lower surface (front surface) of the paper S, and the image of the front surface is formed. The sheet S is discharged to the discharge unit 605 with the lower surface (surface) on which the image is formed facing downward. When the print side priority mode 503 is ON in single-sided printing, the sheet S is transported along the transport path for double-sided printing shown in FIG. 6 instead of the transport path shown in FIG. However, no image is formed on the upper surface (back surface) of the paper S set in the feed cassette 601, the image on the front surface is formed on the lower surface (front surface) of the paper S, and the image on the front surface is formed on the lower surface (front surface). ) facing downward, the sheet S is discharged to the discharge unit 605 .

According to this embodiment, when the print surface priority mode of the paper ID of the paper S is ON, the lower surface (front surface) of the paper S set in the feed cassette 601 is printed regardless of single-sided printing or double-sided printing. image is formed. Then, the sheet S is discharged to the discharge unit 605 with the lower surface (surface) on which the image on the surface is formed facing downward (in the same direction). That is, according to this embodiment, when the print side priority mode of the paper ID of the paper S is set, the paper S is transported to the re-transport path 612, which is the transport path for double-sided printing, in single-sided printing. As a result, in both single-sided printing and double-sided printing, the sheet S can be discharged to the discharge unit 605 with the lower surface (front side) on which the image on the front side is formed facing downward. It can prevent the time from becoming long.

With reference to FIG. 7, in the MFP 100, which side of the sheet set in the feed cassette 601 should be formed with the image on the top side or the bottom side of the single-sided printing or the double-sided printing will be described. FIG. 7 is an explanatory diagram showing on which side the front side image is formed, the upper side or the lower side of the paper. It is assumed that sheets (preprinted sheets) having different front and back sides are stacked in the feed cassette 601 . For convenience of explanation, as shown in FIG. 7A, the upper surface of the paper set in the feed cassette 601 is blank, and the lower surface of the paper is printed with the character "bottom". FIG. 7B is a diagram showing an example of a sheet on which an image is formed on the front side when the print side priority mode is OFF in single-sided printing. The image of the surface is printed on the upper surface of the first to third sheets of paper. FIG. 7C is a diagram showing an example of a sheet on which an image on the front side and an image on the back side are formed in double-sided printing. In MFP 100, in order to eject the front side of the paper facedown, the back side image is first formed on the upper side of the paper, and then the paper is reversed and the front side image is formed on the lower side of the paper. Here, as can be seen by comparing FIGS. 7B and 7C, single-sided printing and double-sided printing are different in that the surface on which an image is formed is the upper surface and the lower surface of the paper, respectively. In this embodiment, since the front side of the paper is printed on the bottom side of the paper in single-sided printing as well as in double-sided printing, when paper with different front and back sides is set and a paper ID with the print side priority mode ON is set, single-sided printing is performed. The paper is conveyed to the re-conveyance path 612 also for printing. FIG. 7D is a diagram showing an example of a sheet on which an image is formed on the front side when the print side priority mode is ON in single-sided printing. The front side image is printed on the bottom side of the first to third sheets. As can be seen by comparing FIG. 7(c) and FIG. 7(d), in single-sided printing and double-sided printing, the surface on which an image is formed on the front side is the bottom surface of the paper, and both sides match.

(printing operation)
FIG. 8 is a flowchart showing the printing operation executed by CPU 201. As shown in FIG. In this embodiment, the CPU 201 of the controller 101 determines whether or not to switch the print setting from single-sided printing to double-sided printing according to whether the print side priority mode is ON. A print operation program is stored in the ROM 210 or the DISK 211 . The CPU 201 reads the program from the ROM 210 or DISK 211 to the memory 202 and executes the printing operation.

When the printing operation starts, in S701 the CPU 201 accepts a print job. In step S<b>702 , the CPU 201 acquires information indicating whether the print setting is single-sided printing or double-sided printing from the settings of the print job received in step S<b>701 . An example of a print job setting method will be described with reference to FIG. FIG. 9 is a diagram showing a print driver screen 1001 when instructing printing from the PC 107. As shown in FIG. The user selects "specify by paper type" 1002 in the box of "paper specification method" in the paper feed tab. The print job includes, as paper designations, a paper feed section designation for designating paper in a paper feed section and a paper type designation for designating paper in a paper type. A paper feed unit is selected according to the paper specification. Here, "specify by paper type" 1002 is selected instead of "specify by paper feed unit". The user designates the paper type in box 1003 . Here, paper ID 1 is designated. Paper ID 1 is set for the print job. Based on the settings of the print job, CPU 201 causes MFP 100 to execute the printing operation of printing on the paper with paper ID 1 . FIG. 10 is a diagram showing a data structure 1101 of a print job. The print job settings include number of copies, paper feed unit designation, paper size designation, paper type designation 1102 and single-sided/double-sided printing designation 1103 . In the example of the data structure 1101 shown in FIG. 10, the paper type designation 1102 designates paper ID 1 as the paper type, and the single-sided/double-sided printing designation 1103 designates single-sided printing.

In S703, the CPU 201 determines whether or not the print setting is single-sided printing from the information acquired in S702. If the print setting is double-sided printing (NO in S703), the CPU 201 advances the process to S709. On the other hand, if the print setting is single-sided printing (YES in S703), the CPU 201 advances the process to S704. In step S<b>704 , the CPU 201 acquires paper type designation information from the received print job settings. In step S<b>705 , the CPU 201 selects a paper feed unit for feeding paper based on the paper type designation information. In S706, the CPU 201 acquires the paper attributes of the paper stacked in the selected paper feed unit.

The correspondence relationship between the paper feed unit and the paper attributes will be described with reference to FIG. 11 . FIG. 11 is a diagram showing the data structure of paper feed units and paper types. A data structure 1201 that associates each of the first sheet feeding unit 631, the second sheet feeding unit 632, the third sheet feeding unit 633, and the fourth sheet feeding unit 634 with the sheet type is stored in the memory 202 or the DISK 211. FIG. The paper type associated with each paper feed unit is designated as paper ID1, paper ID2, or paper ID3. For example, as shown in FIG. They are designated as paper ID3. The data structure of the paper attributes 1211, 1212, and 1213 associated with paper ID1, paper ID2, and paper ID3 is saved in the memory 202 or the DISK 211. FIG. Information indicating whether the print surface priority mode (preprinted paper) associated with each paper ID is ON or OFF can be obtained from the data structure of the paper attributes 1211 , 1212 , and 1213 . The setting values of the paper attributes 1211, 1212, and 1213 can be changed from the paper attribute setting screen 501 shown in FIG.

For example, if the paper type is paper ID1, the CPU 201 automatically selects the first paper feeding unit 631 or the third paper feeding unit 633 in S705, and acquires the paper attribute 1211 of paper ID1 in S706. If the paper type is paper ID2, the CPU 201 automatically selects the second paper feeding unit 632 in S705, and acquires the paper attribute 1212 of paper ID2 in S706. When the paper type is paper ID3, the CPU 201 automatically selects the fourth paper feeding unit 634 in S705, and acquires the paper attribute 1213 of paper ID3 in S706.

In S707, the CPU 201 determines whether or not pre-printed paper (hereinafter referred to as print side priority mode) is ON based on the paper attributes acquired in S706. If the print side priority mode is ON (YES in S707), the CPU 201 advances the process to S708. In step S<b>708 , the CPU 201 inserts image data of the blank side as image data of the back side into the image data of single-sided printing. In S709, the CPU 201 performs double-sided printing. As described above, in double-sided printing, the paper is passed through the re-conveyance path 612 without printing on the first side (upper side) of the paper, and after the paper is reversed, the front side image is printed on the second side (lower side) of the paper. Form. As a result, the front side image is printed on the bottom surface of the paper set in the first paper feeding section 631 or the third paper feeding section 633, and the paper is delivered to the discharge section 605 with the bottom side on which the front side image is printed facing downward. Ejected. CPU 201 terminates the printing operation. On the other hand, if the print surface priority mode is OFF (NO in S707), the CPU 201 advances the process to S710. In S710, the CPU 201 performs single-sided printing in the speed priority mode (first mode) described with reference to FIG. A surface image is formed on the first surface (upper surface) of the paper, and the paper is discharged to the discharge unit 605 without passing through the re-conveyance path 612 . CPU 201 terminates the printing operation.

According to this embodiment, when printing an image on paper with different front and back sides, the paper set in the paper feed unit with the front side facing down for double-sided printing is turned upside down for single-sided printing. There is no need to re-set it in the paper feed unit. According to this embodiment, single-sided printing can be performed in the speed priority mode (first mode) or the print side priority mode (second mode) according to the attribute information corresponding to the paper type.

Example 2 will be described below. In Example 2, structures similar to those in Example 1 are denoted by the same reference numerals, and descriptions thereof are omitted. The MFP 100, the control system 10, the operation unit 106, the paper attribute setting screen 501, the paper transport path, and the printing operation of the second embodiment are the same as those of the first embodiment, so description thereof will be omitted. In the first embodiment, a print job includes a paper specification specifying a paper in a paper feed unit or a paper specification specifying a paper by a paper type. A paper feed unit is selected according to the paper specification. On the other hand, in the MFP 100 of the second embodiment, when neither the paper feed unit nor the paper type is specified in the print job, the paper feed unit for which the preprint paper (print side priority mode) is ON is excluded. Automatically select the paper source. The automatic paper feed unit selection according to the second embodiment will be described below.

(Paper source automatic selection)
The automatic paper feed unit selection according to the second embodiment will be described below with reference to FIGS. 12 and 13. FIG. FIG. 12 is a flow chart showing the automatic paper feed unit selection operation executed by the CPU 201. As shown in FIG. In this embodiment, the CPU 201 of the controller 101 determines automatically selectable paper feed units based on the ON/OFF state of preprinted paper (hereinafter referred to as print surface priority mode) set in the paper attribute 502 . A program for automatically selecting a paper feeding unit is stored in the ROM 210 or the DISK 211 . The CPU 201 reads the program from the ROM 210 or DISK 211 to the memory 202 and executes the automatic paper feed unit selection operation.

When the paper feed unit automatic selection operation is started, in S901, the CPU 201 accepts a print job. In S<b>902 , the CPU 201 determines whether the print job received in S<b>901 includes paper feed unit designation or paper type designation. If the print job includes paper feed unit designation or paper type designation (YES in S902), the CPU 201 advances the process to S903. In S903, the CPU 201 selects a paper feed unit according to the paper feed unit designation or the paper type designation. The CPU 201 terminates the paper feed unit automatic selection operation. On the other hand, if the print job does not specify the paper feed unit or paper type (NO in S902), the CPU 201 advances the process to S904. In step S<b>904 , the CPU 201 determines whether or not sheet attributes have been acquired from all sheet feeding units for which automatic selection is set.

Here, referring to FIG. 13, a setting method for automatically selecting the paper feed unit will be described. FIG. 13 shows screens 511 and 512 for setting automatic selection of the paper feed unit. Screens 511 and 512 are displayed on the liquid crystal display unit 401 of the operation unit 106 . FIG. 13A is a diagram showing a screen 511 for selecting a job for setting automatic selection of a paper feed unit. A screen 511 shown in FIG. 13A for setting automatic selection of the paper feed unit is displayed on the liquid crystal display unit 401 . ON/OFF of paper feed unit automatic selection can be set for each job type such as "copy" and "printer". When the copy button 801 in the screen 511 shown in FIG. 13A is touched, a screen 512 shown in FIG. FIG. 13B shows the setting button 802 of the first sheet feeding unit 631, the setting button 803 of the second sheet feeding unit 632, the setting button 804 of the third sheet feeding unit 633, and the setting button 804 of the third sheet feeding unit 633, which can be set to automatically select in a copy job. FIG. 11 is a diagram showing a setting button 805 of a four-sheet feeding unit 634; Since the setting buttons 802, 803, and 804 are set to ON in the example shown in FIG. Subject to automatic selection. Since the setting button 805 is set to OFF, the fourth sheet feeding unit 634 is excluded from automatic selection targets. Information about the setting of the automatic selection target of the paper feed unit is saved in the memory 202 .

If the paper attributes have not been acquired from all the paper feed units for which automatic selection is set (NO in S904), the CPU 201 acquires the paper attribute 1211 of the first paper feed unit 631, which is the target of automatic selection, in S905. do. The correspondence relationship between the paper feed units and the paper attributes in the second embodiment is the same as in the first embodiment described with reference to FIG. In S906, the CPU 201 determines whether the print surface priority mode is ON from the paper attribute 1211 acquired in S905. In the example of FIG. 11, the print surface priority mode of the paper attribute 1211 of the first paper feed unit 631 is ON (YES in S906), so in S907 the CPU 201 excludes the first paper feed unit 631 from automatic selection targets. . The CPU 201 returns the process to S904.

Since the paper attributes have not been acquired from all the paper feed units for which automatic selection is set (NO in S904), the CPU 201 acquires the paper attributes 1212 of the second paper feed unit 632, which is the target of automatic selection, in S905. do. In S906, the CPU 201 determines whether the print surface priority mode is ON from the paper attribute 1212 acquired in S905. In the example of FIG. 11, the print side priority mode of the paper attribute 1212 of the second paper feeding unit 632 is OFF (NO in S906), so the CPU 201 makes the second paper feeding unit 632 an automatic selection target in S908. . The CPU 201 returns the process to S904.

Since the paper attributes have not been acquired from all the paper feed units for which automatic selection is set (NO in S904), the CPU 201 acquires the paper attribute 1211 of the third paper feed unit 633, which is the target of automatic selection, in S905. do. In S906, the CPU 201 determines whether the print surface priority mode is ON from the paper attribute 1211 acquired in S905. In the example of FIG. 11, the print surface priority mode of the paper attribute 1211 of the third paper feeding unit 633 is ON (YES in S906), so the CPU 201 excludes the third paper feeding unit 633 from automatic selection targets in S907. . The CPU 201 returns the process to S904.

Since the fourth paper feed unit 634 is excluded from automatic selection targets, the CPU 201 determines in S904 that the paper attributes have been acquired from all the paper feed units for which automatic selection is set (YES in S904). Terminate the paper feed unit automatic selection operation. In this way, in the example shown in FIG. 11, the print side priority mode is selected from the first paper feed unit 631, the second paper feed unit 632, and the third paper feed unit 633 set as automatic selection targets in the example shown in FIG. The first sheet feeding unit 631 and the third sheet feeding unit 633 that are ON are excluded. As a result, only the second sheet feeding unit 632 is set as an automatic selection target.

According to this embodiment, the paper feed unit associated with the paper attribute in which the print surface priority mode is set to ON is excluded from automatic selection targets. Therefore, even if the paper feed unit is automatically selected, paper with different front and back sides stacked in the paper feed unit linked to the paper attribute for which the print side priority mode is set to ON is incorrect. It is possible to prevent the image of the front side from being formed on the back side of the paper due to the paper being fed through the back side.

100 MFP (image forming apparatus)
201 CPU (control unit)
202 Memory (storage unit)
211 DISK (storage unit)
302 Printer unit (image forming unit)
601 Feeding cassette (feeding unit)
605... Discharging part 611... Conveying path 612... Re-conveying path 624... Reversing part

Claims (5)

a paper feed unit having a plurality of cassettes on which paper is stacked;
a transport path along which the paper fed from the paper feed unit is transported;
an image forming unit that forms an image on the sheet conveyed on the conveying path;
a reversing unit for reversing the paper that has passed through the image forming unit;
a re-conveying path through which the sheet reversed by the reversing section is conveyed;
a discharge unit for discharging the paper on which the image is formed;
a storage unit that stores attribute information corresponding to paper types;
a control unit that receives a print job including the paper type and print settings for single-sided printing or double-sided printing;
When the print setting is the double-sided printing, the control unit causes the image forming unit to form an image on the first surface of the sheet transported from the first cassette of the plurality of cassettes to the transport path, and The sheet on which the image is formed is reversed by the reversing section, and an image is formed by the image forming section on the second side opposite to the first side of the sheet conveyed to the conveying path through the re-conveying path. , ejecting the paper to the ejection unit;
When the print setting is single-sided printing, the control unit determines which of the first mode and the second mode to execute based on the attribute information corresponding to the paper type included in the print job. to judge
When executing the first mode, the control unit causes the image forming unit to form an image on the first surface of the sheet conveyed from the first cassette to the conveying path, and the image is formed on the first surface of the sheet. discharging the paper to the discharge unit without passing through the re-conveyance path;
When executing the second mode, the control unit causes the image forming unit to not form an image on the first surface of the sheet transported from the first cassette to the transport path, and the sheet is transported to the transport path. The image forming section forms an image on the second side opposite to the first side of the sheet reversed by the reversing section and conveyed to the conveying path through the re-conveying path, and discharges the sheet to the discharging section. death,
The paper is discharged to the discharge unit with the upper surface of the paper stacked in the first cassette in a different orientation between the double-sided printing and the single-sided printing in which the first mode is set,
The paper is ejected to the ejection section in the same direction for the upper surface of the paper stacked in the first cassette for the double-sided printing and for the single-sided printing in which the second mode is set. image forming device. 2. The method according to claim 1, wherein when the print setting is double-sided printing, the control unit forms an image of the back side on the first side and an image of the front side on the second side. Image forming device. When the print setting is single-sided printing and the second mode is to be executed , the control unit sets image data of a blank page as image data of the first page, and sets the image data of the blank page as the image data of the first page. 3. The image forming apparatus according to claim 1, which forms an image of . The storage unit stores a correspondence relationship between the plurality of cassettes and the paper types,
The print job includes a paper supply unit specification in which whether or not to specify the paper in the cassette and a paper type specification in which whether or not to specify the paper by the paper type,
4. The control unit selects the first cassette from the plurality of cassettes according to the paper type when the print job is set to specify the paper by the paper type. The image forming apparatus according to any one of . When the print job is set to not specify the paper in the cassette and the paper type is set to not specify the paper, the control unit sets the attribute information corresponding to the paper type to the second mode. 5. The image forming apparatus according to claim 4, wherein the first cassette corresponding to the paper type for which is set is not selected.

Images